A reliable, robust assay system which can be deployed to a point of care is useful in a number of settings. For example, where there is an infectious disease outbreak in a remote area (e.g., the recent Ebola outbreaks), such an assay is of benefit for arresting the outbreak as quickly as possible (infected individuals can be quickly located then isolated) and for keeping health care providers safer.
An assay driver system can be used to automate an assay. One type of assay driver induces movement of magnetic beads which contact sample (or control) and then carry it into contact with assay reagents. The movement has to be carefully timed, to ensure proper reaction times in different reagents. The results must also be readable for fast interpretation. One type of discontinuous point of care assay system with an assay driver suitable for use herein is disclosed in US Publ'n No. 2017/0102384 (incorporated by reference). This application discloses a substantially transparent cartridge having wells containing various assay reagents. Magnetic beads also reside in the wells, and the magnetic beads are moved among the wells in order to carry sample into contact with different assay reagents in different wells. It also discloses that a preferred material for sealing one side of the cartridge, in a manner such that only the channels connecting the wells are open to the outside, and the open side of the wells are sealed, is a translucent plastic paraffin film, including but not limited to Parafilm®. It is noted that the magnetic beads will be attracted towards the paraffin film during the assay, and will move along its inside surface during their movement among the wells. The inner side of paraffin film allows such movement. The assay is more user-friendly for point of care use, if it is shipped to the point of care with the magnetic beads and assay reagents (and preferably, control solution) loaded in the wells—leaving only sample for the point of care operator to load. The other side of the cartridge, with the openings for the channels, can be sealed with tape or other material—for shipment or storage. The tape may or not be needed to be removed to conduct the assay at the point of care.
Even with both sides of the cartridge sealed (by tape on one side and a preferred material on the other), the reagents, magnetic beads or other materials in the wells may tend to migrate out of the wells or into the channels during transport. It is desirable to stop such potential migration, so all items start in the appropriate well when the assay is conducted at the point of care. If a gel is used to maintain materials in wells, it is useful to have a temperature indicator associated with the assay, so the temperature at which the gel melts—whereupon reagents, magnetic beads or other materials can be moved among wells during the assay—is indicated.